Thermal diffusion apparatus



May 13, 1958 J. w. THOMAS THERMAL DIFFUSION APPARATUS Filed July 26, 1954 2 Sheets-Sheet 1 7 w w a /xflz wfizfi z/ h @523 3??? 4 Z Q/ WVK W Q Q Q Q 359 3 W 3 O l 3 3 2 2 INVENTOR.

JOHN w. THOMAS fyx May 13, 1958 J. w. THOMAS THERMAL DIFFUSION APPARATUS Filed July 26, 1954 2 Sheets-Sheet 2 u a w w m A A m J, /y// wfi p fi W: m Wm z??? fl/ /x/flfi A m J 362%? 56%? A m H A w M/Z/W/M/ fi/ fi ...,W..| 2 w w AMT p6??? w z C M, wm zy/ A E w %/Z A M 2 9??? ,1 A x429? 1 w /y w/ fi /Q A Q ?#//%Q A; Z/A xxx/449% m fl fiwy wmw/ V n l Ad 2 H 2 m in o A 2,834,467 THERMAL DIFFUSION APPARATUS John W. Thomas, Cleveland, Ohio, assignor to The Standard Oil Company, Cleveland, Ohio, a corporation of Ohio Application July 26, 1954, Serial No. 445,547

7 Claims. 01. 210-176) The present invention relates to thermal diffusion apparatus and, more particularly, to novel and improved distribution of the fluid in the apparatus.

Thermal diffusion is a term used herein to define a process in which a mixture, liquid under operating conditions, is separated into two or more fractions which differ in composition from the composition of the original mixture, said separation is brought about by the imposition of a temperature gradient across a space through which the liquid is conducted.

In thermal diffusion apparatus comprising a multiplicity of alternate relatively hot and cold opposed surfaces having separation chambers formed therebetween, it has been proposed to feed the fluid which is to be separated through the side of each surface-forming element to a reservoir behind a port or slot which extends for substantially the breadth of the separation chamber fed by the reservoir, and then from the reservoir through said slot or port in the surface-forming element into the separation chamber. The manufacture of the individual surface-forming elements for this type of distribution systern is both complex and expensive. Further, since individual reservoirs are required for each of the surfaceforming elements, it is diflicult to manifold the several reservoirs so that each will receive anequal amount of feed and full utilization can be made of all theseparation surface contained in the apparatus.

It is an object of the invention, accordingly, to provide novel and improved distribution means, wherein a large number of the reservoirs in a thermal diffusion apparatus are eliminated, thereby permitting the reduction of plate thickness and producing a substantial reduction in cost and space requirements while still accomplishing satisfactory distribution of the fluid.

In accordance with the invention, there is provided a multi-plate thermal diifusion apparatus, wherein a plurality of separation chambers or slits may be arranged in a parallel manner and have the fluid which is to be separated therein fed from a common reservoir or header and the separation products Withdrawn to common output reservoirs or headers.

For a more complete understanding of the invention reference may be had to the following detailed description of an exemplary embodiment of the invention taken in conjunction with the accompanying figures of the drawing, in which:

Figure 1 is a view in vertical section of a multi-plate, thermal diffusion apparatus in accordance with the invention;

Figure 2 is an isometric view, in side elevation, of a typical plate showing the distribution slots;

Figure 3 is a view in vertical section of a thermal diffusion apparatus also in accordance with the invention; and

Figure 4 is an isometric view of a reservoir-containing plate, partially cut away so as to reveal the reservoir details.

Unite States Patet Referring now to Figure l, a conduit 10 leads from a supply of the fluid which is to be separated into a header, or feed reservoir 11 formed by a semi-cylindrical housing 12 mounted on an end plate 14 of the thermal diifusion apparatus. The reservoir extends the width of the plate and is closed at the ends. The end plate 14 is arranged with intermediate plates 15 and another end plate 18 to form a plurality of separation chambers, or slits, 19. The spacing between adjacent plates and the fluid-tightness of the respective separation chambers 19 are provided by suitable gasket and spacer means 20.

Each of the plates 14, 15, and 18 may have their temperatures regulated in accordance with thermal diffusion techniques. For example, the plates 14, 15 and 13 may each include a plurality of appropriately connected conduits 21, a heat transfer fluid such as Dowtherm may be pumped through the conduits 21 in the hot plates, and a different heat transfer fluid such as water may be pumped through the conduits 21 in the cold plates. The plates are alternately heated and cooled so that each slit 19 has a hot and a coldsurface. I

The end plate 14 has a.slot 25 having a configuration such as that shown in Figure 2, which is located centrally within the plate 14 and is substantially coextensive with the breadth of the separation chamber 19 situated between adjacent plates. The slot 25 in plate 14 permits the separation chamber 19 to be in communication with the feed reservoir 11.

Each of the intermediate plates 15 has a corresponding slot 25 similarly centrally located and of substantially the same configuration, as shown in greater detail in Figure 2. Thus the feed reservoir 11 is in communication with several parallel separation chambers 19, by means of the slots 25 in a series of plates 15 as shown in Figure 1.

The slots-25 preferably have a dimension Y, as shown in Figure 2, that is many times larger than the spacing between adjacent plates defining the separation chamber 19, so as to maintain equal distribution of the fluid between the several separation chambers 19. In order to maintain the pressure drop between the points P1, reservoir 11 in Figure 1, and P2, the input to the furthest separation chamber, at a very small value, the feed area XY of a slot 25 is made equal to two times the number of separation chambers times the dimension X times the spacing between the plates forming the separation chamber.

Withdrawal from each of the separation chambers 19 'is achieved in a similar manner by means of slots 26 and 28 which are spaced on opposite sides of the slots 25 in each of the intermediate plates 15 at points near the extremities of the separation chambers 19. The slots 26 and 28 preferably have the same dimensions and configuration as the slots 25. The end plate 18 includes the two slots 26 and 28 spaced apart at opposite ends of the plate 18 and aligned with the slots 26 and 28, respectively, of the intermediate plates 15, thereby completing withdrawal channels from the separation chambers 19.

The output headers or reservoirs 30 and 31 are formed by semi-cylindrical housings 32 and 33, respectively, which are mounted on the outer wall of the end plate 18. The slots 26 and 23 form channels in which the fluid separation products are withdrawn from the parallel separation chambers 19 to output headers 30 and 31. Output conduits 35 and 36 serve to conduct the fluid separation products from their respective output reservoirs 30 and 31 to any desired location.

When a large number of separation chambers are utilized, it is desirable to employ intermediate feed plates, such as the intermediate feed plate 16 shown inFi-gures 3 and 4, at frequent intervals along the line of multiple plates. The intermediate feed plate 16 may serve as either a hot or cold plate depending upon its position within the array of alternate hot and cold plates, and contains the necessary conduits 21 through which the appropriate heat transfer fluid is passed. The intermediate feed plate 16 includes a centrally located feed or input reservoir 39 which is centrally located within the plate 16 and communicates with the slots of subsequent intermediate plates 15 by means of a slot 40 which is substantially coextensive with the breadth of the adjacent separation chamber 19. The input or feed reservoir 39 is fed through a conduit 41 communicating with the exterior of the plate.

Spaced apart from and on opposite sides of the input or feed reservoir 39 are two output or withdrawal reservoirs 45 and 46, respectively, which are in communication with the slots 26 and 28 of a preceding group of plates 15 by means of respective slots 48 and 49 which are substantially coextensive with the breadth of the separation chamber 19 with which they communicate and are aligned with the slots 26 and 28, respectively. The output or withdrawal reservoirs 45 and 46 are connected to a suitable location by means of the conduits 5t) and 51, respectively.

Thus there has been provided novel and improved distribution means for the fluid which is to be separated by the separation chambers of a multi-unit thermal diffusion apparatus. As a result of this type of distribution, all of the plates may have much less thickness than the conventional type of plate which contains input and/ or output reservoirs and ports, and all of the plates with the exception of the intermediate feed plate 16 and the end plates 14 and 18 may be identically constructed. Since thermal dittusion apparatus of this type may contain as many as 30 or 50 parallel alternate hot and cold plates,

it is readily apparent that a substantial saving in cost and space may be achieved, in accordance with the invention.

It will be obvious to those skilled in the art that the above disclosed embodiment is meant to be merely exemplary, and that it is susceptible of modification and variation without departing from the spirit and scope of the invention.

Likewise, while the apparatus has been described in connection with a center feed-end product How pattern, other flow patterns may be employed with the apparatus of this invention. For example, the feed may be introduced at the top of one of the end plates and the products may be withdrawn from the top and bottom of the other end plate. Changes in the construction of this apparatus in order to accommodate fiow patterns other than those herein described are included within the scope of this invention as being obvious to those skilled in the art. Accordingly, the invention is not deemed to be limited except by the appended claims.

I claim:

1. A plate adapted to form at least one side of a liquid thermal diffusion separation chamber comprising heat transfer means and having at least three slots therein in order to provide communication between adjacent separation'chambers formed by a plurality of said plates, said slots being substantially co-extensive with the breadth of said separation chamber.

2. A plate adapted to form at least one side of a liquid thermal diflusion separation chamber comprising heat transfer means and having at least three slots therein in order to provide communication between adjacent separation chambers formed by a plurality of said plates, said slots being substantially co-extensive with the breadth of said separation chamber and spaced apart equidistantly on the face of said plate.

3. A plate adapted to form one side of two liquid thermal difiusion separation chambers having first and second slots therein, each separately communicating with the same face of said plate, liquid reservoirs in said plate communicating with said slots, a third slot communicating with the opposite face of said plate, a liquid reservoir in said plate communicating with said third slot, said third slot located between and substantially equidistantly from said first and second slots, all of said slots being substantially co-extensive with the breadth of said separation chamber.

4. A plate adapted to form one side of two liquid thermal diffusion separation chambers having first and second slots therein, each separately communicating with the same face of said plate, liquid reservoirs in said plate communicating with said slots, a third slot communicating with the opposite face of said plate and located between said first and second slots, and a liquid reservoir in said plate communicating with said third slot, all of said slots being substantially coextensive with the breadth of said separation chamber.

5. A plate constructed according to claim 3 having a plurality of coils embedded therein.

6. A plate constructed according to claim 4 having a plurality of coils embedded therein.

7. In a thermal diifusion apparatus comprising a uniformly aligned array of flat plate members spaced apart so as to form a plurality of separation chambers therebetween and means for imposing a uniform temperature gradient across each of said separation chambers, the improvement comprising an arrangement of the plate members wherein the first plate member of said array is provided with a liquid reservoir means and a longitudinal opening communicating with said reservoir means, the last plate member of said array is provided with at least two liquid reservoir means and longitudinal openings communicating with said reservoir means, and plate members intermediate between said first and last plates of said array are provided with at least three longitudinal openings therein so that a liquid may flow freely between said reservoir means and all of said separation chambers.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A PLATE ADAPTED TO FORM AT LEAST ONE SIDE OF A LIQUID THERMAL DIFFUSION SEPARATION CHAMBER COMPRISING HEAT TRANSFER MEANS AND HAVING AT LEAST THREE SLOTS THEREIN IN ORDER TO PROVIDE COMMUNICATION BETWEEN ADJACENT SEPARATION CHAMBERS FORMED BY A PLURALITY OF SAID PLATES, 